<?php

    function b64get($name) {
        return isset($_GET[$name]) ? base64_decode($_GET[$name]) : null;
    }

    function fowner($filename) {
        return posix_getpwuid(fileowner($filename))['name'];
    }

    function fgroup($filename) {
        return posix_getpwuid(fileowner($filegroup))['name'];
    }

    function faccess($filename) {
        return substr(sprintf('%o', fileperms($filename)), -4);
    }

    $dir = b64get('d');

    if( is_null($dir) )
        $dir = '.';

    $file = b64get('f');

    $basef = "fm.php";

    $path = $dir .'/' . $file;

    if( isset($_GET['dl']) ) {
        if ( file_exists($path) ) {

            if( !is_readable($path) )
                die('not readable');

            header('Content-Description: File Transfer');
            header('Content-Type: application/octet-stream');
            header('Content-Disposition: attachment; filename="'.basename($file).'"');
            header('Expires: 0');
            header('Cache-Control: must-revalidate');
            header('Pragma: public');
            header('Content-Length: ' . filesize($path));

            readfile($path);

            exit;
        } else
            die('file not exists');
    }

    $o = opendir($dir);

    $dirs = [];
    $files = [];

    while( ($f = readdir($o)) != false ) {
        $p = $dir .'/' . $f;

        if( is_dir($p) )
            $dirs[] = $f;
        else if( is_file($p) )
            $files[] = $f;
    }

?>
Directory: <b><?php echo $dir; ?></b><br>

<table width="100%" border="1">
    <tr>
        <th>Name</th>
        <th>O - G - A</th>
        <th>Size</th>
        <th>Download</th>
    </tr>
<?php
    foreach ($dirs as $d) {
        $p = $dir .'/' . $d;
        ?>
        <tr>
            <td>
                <a href="<?php echo $basef .'?d='. base64_encode($p); ?>"><?php echo $d; ?></a>
            </td>
            <td>
                <?php
                    echo fowner($p) . ' - ';
                    echo fgroup($p) . ' - ';
                    echo faccess($p);
                ?>
            </td>
            <td colspan="2"></td>
        </tr>
        <?php
    }

    foreach ($files as $f) {
        $p = $dir .'/' . $f;
        ?>
        <tr>
            <td><?php echo $f; ?></td>
            <td>
                <?php
                    echo fowner($p) . ' - ';
                    echo fgroup($p) . ' - ';
                    echo faccess($p);
                ?>
            </td>
            <td><?php echo filesize($p) ?></td>
            <td>
                <a href="<?php echo $basef . '?dl&d=' . base64_encode($dir) . '&f=' . base64_encode($f); ?>" target="_blank">Download</a>
            </td>
        </tr>
        <?php
    }
?>
</table>